Suture length adjustment for minimally invasive heart valve repair

ABSTRACT

Disclosed herein are various embodiments of suture adjustment mechanisms for anchors configured to be inserted into a heart wall of a patient to anchor a suture as an artificial chordae under an appropriate tension for proper valve function. Suture adjustment mechanisms can be configured to retain suture ends extending from the leaflet to the anchor with sufficient force to prevent natural movement of the leaflet from adjusting a length of the suture between the anchor and the leaflet. Free ends of the suture can extend from the anchor external to the body as tensioning strands. A surgeon can supply sufficient force on the tensioning strands from external the body to adjust a length and tension of the suture between the anchor and the leaflet.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.62/669,115 filed May 9, 2018, which is hereby fully incorporated hereinby reference.

TECHNICAL FIELD

The present invention relates to minimally invasive delivery of asuture. More particularly, the present invention relates to anchoring ofa suture as an artificial chordae tendineae for a flailing or prolapsingleaflet in a beating heart.

BACKGROUND

The mitral and tricuspid valves inside the human heart include anorifice (annulus), two (for the mitral) or three (for the tricuspid)leaflets and a subvalvular apparatus. The subvalvular apparatus includesmultiple chordae tendineae, which connect the mobile valve leaflets tomuscular structures (papillary muscles) inside the ventricles. Ruptureor elongation of the chordae tendineae results in partial or generalizedleaflet prolapse, which causes mitral (or tricuspid) valveregurgitation. A commonly used technique to surgically correct mitralvalve regurgitation is the implantation of artificial chordae (usually4-0 or 5-0 Gore-Tex sutures) between the prolapsing segment of the valveand the papillary muscle.

This technique for implantation of artificial chordae was traditionallydone by an open heart operation generally carried out through a mediansternotomy and requiring cardiopulmonary bypass with aortic cross-clampand cardioplegic arrest of the heart. Using such open heart techniques,the large opening provided by a median sternotomy or right thoracotomyenables the surgeon to see the mitral valve directly through the leftatriotomy, and to position his or her hands within the thoracic cavityin close proximity to the exterior of the heart for manipulation ofsurgical instruments, removal of excised tissue, and/or introduction ofan artificial chordae through the atriotomy for attachment within theheart. However, these invasive open heart procedures produce a highdegree of trauma, a significant risk of complications, an extendedhospital stay, and a painful recovery period for the patient. Moreover,while heart valve surgery produces beneficial results for many patients,numerous others who might benefit from such surgery are unable orunwilling to undergo the trauma and risks of such techniques.

Techniques for minimally invasive thoracoscopic repair of heart valveswhile the heart is still beating have also been developed. U.S. Pat. No.8,465,500 to Speziali, which is incorporated by reference herein,discloses a thoracoscopic heart valve repair method and apparatus.Instead of requiring open heart surgery on a stopped heart, thethoracoscopic heart valve repair methods and apparatus taught bySpeziali utilize fiber optic technology in conjunction withtransesophageal echocardiography (TEE) as a visualization techniqueduring a minimally invasive surgical procedure that can be utilized on abeating heart. More recent versions of these techniques are disclosed inU.S. Patent Application Publication Nos. 8,758,393 and 9,192,374 toZentgraf, which disclose an integrated device that can enter the heartchamber, navigate to the leaflet, capture the leaflet, confirm propercapture, and deliver a suture as part of a mitral valve regurgitation(MR) repair. These minimally invasive repairs are generally performedthrough a small, between the ribs access point followed by a punctureinto the ventricle through the apex of the heart. Although far lessinvasive and risky for the patient than an open heart procedure, theseprocedures still require significant recovery time and pain.

Some systems have therefore been proposed that utilize a catheter routedthrough the patient's vasculature to enter the heart and attach a sutureto a heart valve leaflet as an artificial chordae. While generally lessinvasive than the approaches discussed above, transcatheter heart valverepair can provide additional challenges. For example, with allartificial chordae replacement procedures, in addition to inserting asuture through a leaflet, the suture must also be anchored at a secondlocation, such as at a papillary muscle in the heart, with a suturelength, tension and positioning of the suture that enables the valve tofunction naturally. If the suture is too short and/or has too muchtension, the valve leaflets may not properly close. Conversely, if thesuture is too long and/or does not have enough tension, the valveleaflets may still be subject to prolapse. Proper and secure anchoringof the suture away from the leaflet is therefore a critical aspect ofany heart valve repair procedure for inserting an artificial chordae.However, adjusting length of a suture in a transcatheter procedure isdifficult as it is not possible for the surgeon to physically controlthe suture and its length once the suture is in the heart.

SUMMARY

Disclosed herein are various embodiments of suture adjustment mechanismsfor anchors configured to be inserted into a heart wall of a patient toanchor a suture as an artificial chordae under an appropriate tensionfor proper valve function. Suture adjustment mechanisms can beconfigured to retain suture ends extending from the leaflet to theanchor with sufficient force to prevent natural movement of the leafletfrom adjusting a length of the suture between the anchor and theleaflet. Free ends of the suture can extend from the anchor external tothe body as tensioning strands. A surgeon can supply sufficient force onthe tensioning strands from external the body to adjust a length andtension of the suture between the anchor and the leaflet.

In one embodiment, a suture adjustment mechanism is embodied in ananchor configured to be implanted into a patient's heart wall to anchora suture extending from a valve leaflet of the heart as an artificialchordae. The anchor can include an anchor body and a means for retaininga suture within the anchor body. The means for retaining a suture isconfigured to enable adjustment of a length of the suture extendingbetween the anchor body and the valve leaflet by pulling tensioningstrands of the suture extending from the anchor body out of thepatient's heart while preventing forces applied on the length of thesuture extending between the anchor body and the valve leaflet due tomovement of the leaflet from adjusting the length of the sutureextending between the anchor body and the valve leaflet.

The above summary is not intended to describe each illustratedembodiment or every implementation of the subject matter hereof. Thefigures and the detailed description that follow more particularlyexemplify various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Subject matter hereof may be more completely understood in considerationof the following detailed description of various embodiments inconnection with the accompanying figures, in which:

FIGS. 1A-1K depict various steps in a method of anchoring a suture in abeating heart of a patient to function as an artificial chordaeaccording to an embodiment.

FIGS. 2A-2B depict steps in a method of anchoring a suture in a beatingheart of a patient to function as an artificial chordae according to anembodiment.

FIGS. 3A-3F depict a suture length and tension adjustment mechanismaccording to an embodiment.

FIGS. 4A-4C depict a suture length and tension adjustment mechanismaccording to an embodiment.

FIG. 5 depicts a suture length and tension adjustment mechanismaccording to an embodiment.

FIGS. 6A-6B depict a suture length and tension adjustment mechanismaccording to an embodiment.

While various embodiments are amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit the claimedinventions to the particular embodiments described. On the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the subject matter as defined bythe claims.

DETAILED DESCRIPTION OF THE DRAWINGS

The present disclosure is generally directed to adjusting a lengthand/or tension of sutures inserted as artificial chordae into one ormore heart valve leaflets through an intravascular, transcatheterapproach. A heart valve leaflet may be captured and a suture insertedthrough the leaflet in any manner known in the art. One such leafletcapture catheter and procedure is disclosed in copending U.S. UtilityPatent Application No. 16/363,701, which is hereby incorporated byreference herein. Another transcatheter procedure for inserting anartificial chordae is disclosed in U.S. Patent Publication No.2016/0143737, which is hereby incorporated by reference herein.

Referring to FIGS. 1A-1K, a procedure for anchoring a suture inserted asan artificial chordae in a transcatheter procedure on a beating heart ofa patient following insertion of the suture into a leaflet isschematically depicted. In this embodiment, a loop of suture has beeninserted through the leaflet and the two free ends of the suture theninserted through the loop to form a girth hitch knot around the edge ofthe leaflet. Further detail regarding attaching a suture to a leaflet inthis manner can be found in U.S. Patent Publication No. 2017/0290582,which is hereby incorporated by reference herein.

Following insertion of the suture 20 into the leaflet 11, the deploymentcatheter used to insert the suture is withdrawn through the guidecatheter 14 and the two free ends 22 of the suture 20 are also withdrawnexternal to the body. The suture ends 22 are then attached to an anchorcontained in an anchor driving catheter 30. Alternatively, the anchorcould be pre-attached to the suture prior to insertion of the sutureinto the leaflet. The anchor driving catheter 30 is inserted into theguide catheter 14, routed through the catheter into the body andadvanced passed the leaflet 11 to the heart wall 13 below the valve at,for example, a papillary muscle as shown in FIGS. 1B-1D. The anchordriving catheter 30 is then used to insert the anchor 100 into themyocardium as shown in FIGS. 1D-1G and as described in more detailbelow. Various embodiments of such anchors can be found in U.S.Provisional Patent Application Nos. 62/669,096 and 62/669,123, entitledLow Profile Tissue Anchor for Minimally Invasive Heart Valve Repair andRadial Arm Tissue Anchor for Minimally Invasive Heart Valve Repair,respectively, both of which are hereby incorporated by reference hereinin their entireties.

After insertion of the anchor 100 into the heart tissue, the anchordriving catheter 30 is withdrawn to a position superior of the valve asshown in FIG. 1H and the length and tension of the suture ends 22extending from the leaflet 11 are tested and adjusted until it isdetermined that normal valve function has been achieved. Thisdetermination can be made through use of ultrasonic imaging, forexample. The tension is adjusted through a tensioning strand 24 of thesuture depicted in FIG. 1H. Once the proper length and tension has beendetermined using, for example, transesophageal echocardiography or othernon-invasive methods, the anchor driving catheter 30 is advanced backdown along the tensioning strand 24 and to sever the strand at theanchor 100, or a separate device configured to sever the strand can beused. The entire catheter system, including the anchor driving catheter30 and the guide catheter 14 is then withdrawn from the patient's body.Referring to FIG. 1K, the suture 20 remains in the body extendingbetween the leaflet 11 and the anchor 100 to function as an artificialchordae tendonae.

FIGS. 2A-2B depict further details regarding adjustment of the lengthand tension of the suture 20 according to an embodiment. After initialinsertion of the anchor 100 into the heart wall 13, the free ends 22 ofthe suture 20 extend between the anchor and the leaflet 11 and thetensioning strand 24 of the suture 20 extends out of the body where itis accessible to the surgeon, as described above. FIG. 2A depicts oneexample of an initial configuration prior to suture adjustment. In thedepicted configuration, a length of the suture ends 22 between theanchor 100 and the leaflet 11 is too long such that there is not enoughtension on the leaflet 11, which could cause the leaflet 11 to continueto prolapse. FIG. 2B depicts a final configuration after sutureadjustment. In this configuration, the length of the suture ends 22between the anchor 100 and the leaflet 11 have been shortened to providea tension that enables the leaflet 11 to coapt with the other leafletduring systole while preventing the leaflet 11 from prolapsing. Onceproper suture length and tension has been achieved as shown in FIG. 2B,the tensioning strand 24 can be severed as discussed above.

Disclosed herein are various embodiments of mechanisms that can beemployed to adjust the length and/or tension of a suture as anartificial chordae in procedures such as those described above. Suchmechanisms enable suture adjustment from outside the body in atranscatheter, intravascular procedure.

FIGS. 3A-3E depict a suture adjustment mechanism 200 of a suture anchor100 according to an embodiment. Suture adjustment mechanism 200 can bedisposed adjacent a proximal portion of an anchor body 104 of sutureanchor 100. For sake of clarity, only body portion 104 of suture anchor100 is depicted. Although not shown in these figures for sake ofclarity, suture anchor 100 would further include a distal portion forembedding the anchor into heart tissue, such as, for example thosedisclosed in the toggle anchor and spider anchor applicationsincorporated by references above.

Suture adjustment mechanism 200 includes an actuation tube 202 and apair of pins or bars 204. Actuation tube 202 can surround a portion ofanchor body 104 of anchor 100. Bars 204 can extend transversely across along axis of anchor body 104. Bars 204 can extend through and besupported within opposing apertures 105 through anchor body 104. Bars204 can further extend through and be supported within opposingapertures 205 in the actuation tube 202 adjacent the apertures 105 inthe anchor body 104. In the depicted embodiment, bars 204 can seatwithin apertures 105, 205, in a generally horizontal side-by-side andparallel configuration with each other. An actuation projection 206 onone or both sides of the actuation tube can extend from actuation tube202 into the aperture 205 and can be selectively positioned betweenpins, as will be discussed below.

A suture 20 can extend into anchor body 104 and be wrapped aroundpins/bars as shown in more detail in FIGS. 3B-3D. For sake of clarity,it is noted that only a single suture end is shown in these Figures.However, it should be noted that each suture inserted through a leafletwill have a pair of suture ends attached to the suture adjustmentmechanism 200. As shown in these figures, each suture end 22 extendingfrom the leaflet to the anchor 100 wraps completely around bothpins/bars. The suture 20 then extends between the bars 204 as tensioningstrands 24 extending back out of the body to the surgeon, as describedabove.

The actuation projection 206 of actuation tube 202 can be biased to aproximal position as shown in FIG. 3E and can be actuated downwardly asshown in FIG. 3F to drive the bars 204 apart. In use, when anchor 100 isattached to the anchor delivery catheter 30, the delivery catheter 30can interface with the actuation tube 202 to actuate the projection 206downwardly to force the bars 204 apart. This space between the bars 204enables the anchor 100 to slide along the tensioning strand 24 from aposition outside the body where the anchor 100 is attached to the suture20 to within the heart adjacent the myocardium where the anchor 100 isto be inserted. Following insertion of the anchor 100, the anchordelivery catheter 30 is withdrawn as discussed above. Once the anchordelivery catheter 30 is detached from the actuation tube 202, the tubereturns to the proximal position shown in FIG. 3E and the tensioningstrand 24 of the suture 20 is held between the bars 204 with sufficientforce such that the forces applied on the free ends 22 of the suture(wrapped around the bars 204) by the natural movement of the leaflet towhich the suture is attached are not sufficient to move the suture.However, a surgeon operating the tensioning strands 24 of the suture 20external to the body can supply sufficient force by pulling on thetensioning strands 24 to shorten the distance between the anchor 100 andthe leaflet (see FIGS. 2A-2B). The actuation tube can be utilized torelease the suture tension applied to the valve leaflet in a situationwhere increasing the length of the suture between the anchor and theleaflet is desired by the surgeon following the assessment of the valvefunction. Once the tension and length of the suture 20 have beenproperly adjusted and the tensioning strand 24 is severed as discussedabove, the suture length will be fixed.

FIGS. 4A-4C depict a suture adjustment mechanism 300 according toanother embodiment. Suture adjustment mechanism 300 is similar to sutureadjustment mechanism 200 in that the suture 20 wraps around a pair ofbars or pins 304 contained in a proximal portion of an anchor body 104of suture anchor 100. In contrast to the generally horizontally alignedbars 204 of suture adjustment mechanism 200, the bars 304 of sutureadjustment mechanism 300 are oriented and aligned generally verticallywith respect to each other. Bars 304 can extend through the anchor body104 similar to the embodiment described above.

The suture ends 22 extending between the leaflet and the anchor 100 wraparound the bars 304 and the free ends or tensioning strands 24 extendbetween the bars 304, as shown in FIGS. 4B-4C. A leaf spring 302 can bepositioned within anchor body 104 to apply a force to bias the barstogether, either by directly contacting the lower bar 304 or by contacta housing element that contains the pins. Tension on the suture and thelength between the anchor 100 and the leaflet can be adjusted by pullingon the tensioning strands 24 outside the body with sufficient force topull the suture 20 through the bars 204 and shorten the connection tothe leaflet. In one embodiment, the force required by the surgeon topull the suture through the mechanism is 0.1 pounds. Natural forces ofthe leaflet on the suture ends 22 are not sufficient to pull the suturethrough the bars 304, and because the suture ends 22 are wrapped aroundthe pins 304 such forces increase the inward clamping force provided bybars 304 to the tensioning strands 24 positioned therebetween. Tensioncan be released by exerting force downward onto leaf spring to enablethe pins to spread apart. Such a force can be applied by, for example, acatheter such as delivery catheter 30 as the anchor 100 is advanced fromexternal the body along the suture 20 to the myocardium where it is tobe anchored.

As noted above, in the previous embodiments only a single suture end hasbeen shown for sake of clarity. In practice, each suture will have apair of ends 22 extending from the leaflet and a corresponding pair oftensioning strands 24. In one embodiment, each anchor 100 andcorresponding tensioning mechanism 200, 300 can accommodate a pair ofsutures connected to the leaflet, which therefore includes two pairs (4)of suture ends 22 extending to the leaflet and two pairs (4) oftensioning strands 24 extending out of the body, as depictedschematically in FIG. 5.

FIGS. 6A-6B depict a suture adjustment mechanism 400 defined in ananchor body 104 of an anchor 100 according to a further embodiment.Essentially, this embodiment replaces the pins or bars 204, 304 of theprevious embodiments with apertures 404 formed through opposing sides ofthe anchor body 104. In one embodiment, apertures 404 include a distalaperture 404 a and a proximal aperture 404 b. In the depictedembodiment, the distal apertures 404 a are generally circular and theproximal apertures 404 b are elongate. Suture adjustment mechanism 400can further include a suture wrapping sleeve 402. Suture wrapping sleeve402 can be positioned around the elongate proximal apertures 404 b.

Referring to FIG. 6B, each suture end 22 of a suture 20 extending fromthe leaflet enters into anchor body 104 through an open proximal end ofanchor body 104 and extends into a hollow interior of anchor body 104.The suture ends 22 then extend out of the distal apertures 404 a and arewrapped around the suture wrapping sleeve 402 at the elongate proximalapertures 404 b. The suture 20 then extends back out of the body as apair of tensioning strands 24 for adjusting a length of each respectivesuture end 22 relative to the leaflet. As with previous embodiments, asurgeon can provide sufficient force on the tensioning strands 24 toadjust the length and tension of the suture ends 22, but the naturalforces of the leaflet are insufficient to adjust the wrapped suture ends22.

Various embodiments of systems, devices, and methods have been describedherein. These embodiments are given only by way of example and are notintended to limit the scope of the claimed inventions. It should beappreciated, moreover, that the various features of the embodiments thathave been described may be combined in various ways to produce numerousadditional embodiments. Moreover, while various materials, dimensions,shapes, configurations and locations, etc. have been described for usewith disclosed embodiments, others besides those disclosed may beutilized without exceeding the scope of the claimed inventions.

Persons of ordinary skill in the relevant arts will recognize that thesubject matter hereof may comprise fewer features than illustrated inany individual embodiment described above. The embodiments describedherein are not meant to be an exhaustive presentation of the ways inwhich the various features of the subject matter hereof may be combined.Accordingly, the embodiments are not mutually exclusive combinations offeatures; rather, the various embodiments can comprise a combination ofdifferent individual features selected from different individualembodiments, as understood by persons of ordinary skill in the art.Moreover, elements described with respect to one embodiment can beimplemented in other embodiments even when not described in suchembodiments unless otherwise noted.

Although a dependent claim may refer in the claims to a specificcombination with one or more other claims, other embodiments can alsoinclude a combination of the dependent claim with the subject matter ofeach other dependent claim or a combination of one or more features withother dependent or independent claims. Such combinations are proposedherein unless it is stated that a specific combination is not intended.

1. An anchor configured to be implanted into a heart wall of a heart ofa patient to anchor a suture extending from a valve leaflet of the heartas an artificial chordae, the anchor comprising: an anchor body; andmeans for retaining a suture within the anchor body, wherein the meansfor retaining the suture is configured to enable adjustment of a lengthof the suture extending between the anchor body and the valve leaflet bypulling tensioning strands of the suture extending from the anchor bodyout of the heart while preventing forces applied on the length of thesuture extending between the anchor body and the valve leaflet due tomovement of the leaflet from adjusting the length of the sutureextending between the anchor body and the valve leaflet.
 2. The anchorof claim 1, wherein the means for retaining a suture within the anchorbody is a pair of pins disposed within the anchor body.
 3. The anchor ofclaim 2, wherein the pair of pins are oriented in a generally horizontalconfiguration with respect to each other.
 4. The anchor of claim 2,wherein the pair of pins are oriented in a generally verticalconfiguration with respect to each other.
 5. The anchor of claim 1,wherein the means for retaining a suture within the anchor body is apair of apertures extending through opposing sides of the anchor body.6. The anchor of claim 2, further comprising means for adjusting aclamping force by which the pins retain the suture.
 7. The anchor ofclaim 6, wherein the means for adjusting comprises a leaf spring thatbiases the pins into a compressed configuration to retain the suture bya clamping force between the pins.
 8. The anchor of claim 7, wherein theleaf spring is configured to be engaged to separate the pins to lessenthe clamping force on the suture.
 9. The anchor of claim 6, wherein themeans for adjusting comprises a sleeve extending around the anchor body.10. The anchor of claim 9, wherein the sleeve is configured to beactuated to separate the pins to lessen the clamping force on thesuture.